Pharmaceutical Biotechnology and Biopharmaceutics
What the exam tests
Pharmaceutical Biotechnology and Biopharmaceutics tests biologics, bioavailability, biosimilars, and the fate of protein drugs.
Core rules
- Absolute bioavailability F = (AUCoral × DoseIV)/(AUCIV × Doseoral) × 100. It accounts for both absorption and first-pass loss.
- BCS and IVIVC: in vitro dissolution can predict in vivo behavior only when a validated IVIVC exists; do not assume bioequivalence from a dissolution profile alone.
- Biologics are usually degraded by proteases, not CYP enzymes. Monoclonal antibodies have long half-lives via FcRn recycling; small proteins may be cleared renally.
- Immunogenicity can reduce efficacy and cause infusion reactions; anti-drug antibodies must be monitored in biosimilar comparability.
Worked example
An oral dose of 100 mg gives AUC 40 mg·h/L; an IV dose of 50 mg gives AUC 80 mg·h/L. F = (40 × 50)/(80 × 100) × 100 = 2000/8000 × 100 = 25%. The oral route delivers one quarter of the exposure of the same nominal dose given intravenously. If the doses were equal, the calculation would simplify to AUCoral/AUCIV, but dose normalization is essential when they differ.
Traps
Do not compare AUCs without normalizing for dose; do not apply small-molecule CYP thinking to antibodies; do not call a biosimilar identical to the originator; and do not ignore cold-chain or aggregation risks when interpreting instability.